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Microgrids

Whenever electric service is interrupted in a widespread area, such as with a hurricane, or there are grid failures that cause other problems, such as the California wildfires, someone inevitably proposes the use of microgrids as a solution.

Let’s look at microgrids and see whether they are real solutions or merely a way to promote another agenda.

After hurricane Maria caused widespread devastation in Puerto Rico, there were an abundance of articles on how microgrids could prevent similar devastation in the future.

Microgrids are now being proposed as a solution to wildfires caused by downed power lines and the failures of the utility’s electrical equipment.

There are basically two types of microgrids:

The first is a small area using independently generated electricity for everyday operation but still connected to the grid for power when needed. An example would be a large university or industrial campus where there are cost savings from generating electricity independent of the electric utility. These savings could come about for several reasons such as generating heat, in conjunction with the generation of electricity, for use by the university or industry.

The second type of microgrid is independent and isolated from the grid. There is no connection to the grid.

The reason for the distinction is that in the second type there are no transmission lines connecting the microgrid to external power plants and this could eliminate the possible cause of wildfires from the failure of transmission lines.

Microgrids use natural gas, diesel, wind, or solar to generate the electricity used by customers connected to the microgrid by distribution lines that also utilize transformers, cutouts, reclosers, regulators, and circuit breakers. (See Will Climate Destroy the Utility Industry, for a description of this equipment.

In other words, all the components that could cause wildfires or blackouts are still present within the area covered by the microgrid. In addition, wind turbines can also catch on fire and can easily cause wildfires.

Hurricanes, such as Maria, can still cause wind turbines, solar panels and distribution lines to fail. A Microgrid does not protect the microgrid community from blackouts.

Microgrids can’t be taken in isolation. For example, in California, there are many smaller communities that need to be connected to the grid and they need transmission lines.

Building a microgrid serving one town doesn’t eliminate the need for transmission lines to serve other towns.

Schematic of a microgrid from Wikipedia

The hidden agenda behind microgrids is clean energy. Microgrids are promoted as a package with wind, solar, and storage batteries, to supply all the electricity needed while eliminating the use of fossil fuels. See, Four Minutes for $150 million

Summary

Microgrids can serve a need, such as when cogeneration, i.e., producing both electricity and heat, can make a microgrid more economic.

Microgrids don’t really reduce the risk of wildfires or blackouts since all the components,other than transmission lines, that can be damaged by storms or cause wildfires remain in place.

2 Replies to “Microgrids”

Based on your first paragraph, the primary rationale behind microgrids is resiliency. But that depends on the type of microgrid. Most of the microgrid pilot projects I’m aware of have fossil fuel gensets for backup. I’m not sure if they are grid connected as well.

Anyway you cut it, microgrids are a major investment. Are they subsidized and if so, what parts; just the wind and solar?

I’m referring to microgrids being used to promote distributed generation in support of wind and solar. This would include resiliency. Wind and solar are subsidized.
After Maria, there were many articles written about using microgrids in Puerto Rico to eliminate blackouts.
Now there are California wildfires. Here is a quote from another article:
“Development of microgrid distributed energy infrastructure eliminates tens of thousands of kilometers of power lines running through densely forested wildlands.”
That article is promoting the idea that microgrids can replace the grid as it exists today. The same was true for the articles about Puerto Rico.
With respect to the distinctions of what a microgrid is.
My article mentioned microgrids connected to the grid, including universities etc, where co-generation makes sense.
There are individual homes or even some communities that could be considered microgrids, using generators, such as natural gas, as backup for when the grid fails.
These are not microgrids as proposed by the above quote or by what was written about Puerto Rico.
My intent is to show that microgrids to replace the existing grid are an illusion.
With respect to your second question.
Microgrids, as promoted for distributed generation, usually ignore the other issues, especially of heating. Heating adds an additional complication to the concept of microgrids replacing the grid.